This invention relates to a pressure accumulator at high pressure side and waste heat re-use device for vapor compressed air conditioning or refrigeration equipment, by which a pressure and a temperature, higher than a conventional device, for refrigerant at high pressure side can be maintained so as to increase the rate of heat dissipation and heat absorption capacity, and accordingly the energy efficiency ratio (EER).
Referring to FIG. 1, a fundamental structure of a conventional vapor compressed air conditioning and refrigeration equipment is shown. A liquid separator 1 is connected via a refrigerant pipe 3 to a compressor 2 such that the saturated refrigerant vapor is suctioned into the compressor 2 and compressed therein. Refrigerant vapor compressed by said compressor 2 will reach superheated state, and enter into a condenser 5, so-called condenser or heat dissipater, via a refrigerant pipe 4. Said condenser 5 comprises a plurality of fins and tubes 6 looped there within. Air is introduced into said condenser 5 for the heat dissipation of high temperature superheated refrigerant gas within condenser tubes, by the rotation of blades 7 of one or more sets of propeller fan 8 for heat dissipation fixed on a frame 9.
Superheated refrigerant gas within condenser tubes will transform into saturated gas, then gas and liquid co-existed then saturated liquid phase after energy reduction through heat exchange with outside air. Since the saturated temperature, i.e. the refrigerant boiling temperature under pipe pressure within condenser is higher than the temperature of outside air, the enthalpy of refrigerant can be reduced by the heat dissipation through outside air, which will result in the liquidization of refrigerant vapor. The liquid-vapor ratio is thus increased. The liquid-vapor ratio will reach its maximum at the outlet of said condenser 5. After the end of heat dissipation, the saturated refrigerant liquid will enter into a throttling valve 10 via a refrigerant pipe 11 to conduct an equal-enthalpy expansion process within said throttling valve. The pressure as well as temperature of the refrigerant will become lower after the expansion process. In this case, the saturated refrigerant under the lowering of saturated temperature and low pressure condition is enter into a heat absorptive tube-and-fin assembly 13, so-called evaporator. Since the phase change from liquid to gas of the refrigerant, an equal-pressure (isobaric) process, is in need of latent heat, the heat contained in the room air, at higher-temperature, can be absorbed such that the temperature of the room can be reduced. Then, saturated refrigerant with lower liquid-vapor ratio is sent back to said liquid separator 1 via the collection of a refrigerant pipe 14. Finally, the gas refrigerant is return to the compressor 2 via the refrigerant pipe 3, to complete a closed refrigerantion cycle for the air conditioning or refrigeration equipment. In a conventional technique as shown in FIG. 2, a fundamental structure of vapor compressed air conditioning or refrigeration equipment with a two-stage heat dissipation is shown. A liquid separator 15 is connected via a refrigerant pipe 17 to a compressor 16 such that the saturated refrigerant vapor is suctioned into the compressor 16 and compressed therein. Refrigerant vapor compressed by said compressor 16 will reach superheated state, and enter into a first condenser 19 via a refrigerant pipe 18. Said first condenser 19 comprises a plurality of fins and tubes 20 looped there within. Air is suctioned into said first condenser 19 for the heat dissipation of superheated refrigerant gas within condenser tubes, by the rotation of blades 21 of one or more sets of propeller fan 22 for heat dissipation fixed on a frame 23. Superheated refrigerant gas within said first condenser 19 will transform into saturated phase after energy reduction through heat exchange with outside air. In this case, the refrigerant is at a state with its gas and liquid phase co-existed. Since the saturated temperature, i.e. the refrigerant boiling temperature under pipe pressure is still higher than the temperature of outside air, the enthalpy of refrigerant can still be reduced by the heat dissipation through outside air, which will result in the liquidization of refrigerant vapor. The liquid-vapor ratio is thus increased. The liquid-vapor ratio will reach its maximum value of first stage of heat dissipation at the outlet of said first condenser 19. After the end of heat dissipation, the high liquid-vapor ratio refrigerant will enter into a second condenser 25 via a refrigerant pipe 24. Said second condenser 25 comprises a plurality of fins and tubes 26 looped there within. Air is suctioned into said second condenser 25 for the heat dissipation of saturated refrigerant at higher temperature within condenser tubes 26, by the rotation of a fan 27, for heat dissipation, driven by one or more sets of high-speed motors 28 mounted on a frame 29. Saturated liquid or sub-cooled refrigerant at the outlet of second condenser 25 can be assured. Subsequently, the refrigerant liquid will enter into a throttling valve 31 via a refrigerant pipe 30 to conduct an equal-enthalpy expansion process within said throttling valve. The pressure and temperature of the refrigerant will decrease after the expansion process. In this case, the saturated refrigerant under the lower saturated temperature and low pressure condition enter the evaporator 32. Since the phase change from liquid to gas of the refrigerant, an isobaric process, is in need of latent heat, the heat contained in the room air can be absorbed such that the temperature of the room can be reduced. Then, saturated refrigerant with lower liquid-vapor ratio is sent back to said liquid separator 15 via the collection of a refrigerant pipe 33. Finally, the gas refrigerant is return to the compressor 16 via the refrigerant pipe 17, to complete a closed refrigerantion cycle for the air conditioning or refrigeration equipment with a two-stage heat dissipation.
In the fundamental structure of a conventional vapor compressed air conditioning and refrigeration equipment as shown in FIG. 1, since the refrigerant, being introduced directly into the condenser tubes 6 of said first condenser 5 after passing through compressor 2, and being heat-dissipated by the air suctioned into said first condenser 5 by the rotation of blades 7 of one or more sets of fan 8 for heat dissipation, transforms from gas at high temperature and high pressure superheated state into saturated refrigerant with its gas and liquid co-existed at lower temperature and lower pressure. The heat dissipation efficiency deteriorates due to the reduction of temperature difference which will result in the reduction of temperature gradient. This will cause the liquid-vapor ratio of saturated refrigerant being unable to be raised further to a higher level at the outlet of first condenser 5. This is the reason why the EER value of a conventional vapor compressed air conditioning and refrigeration equipment can not be improved.
The difference of two conventional vapor compressed air conditioning or refrigeration equipment as shown in FIGS. 1 and 2 is the use of a two-stage heat dissipation method, i.e. a two-stage heat dissipation device including a heat dissipated first condenser 19 and a second condenser 25 as shown in FIG. 2. In order to have better heat dissipation and to ensure the increase of liquid-vapor ratio of saturated refrigerant, a first condenser 19 is used to dissipate the heat of superheated refrigerant gas and a secondary condenser is used to dissipate the heat of saturated refrigerant. The heat was removed by the air introduced into said both condensers. Then, the refrigerant is circulated back to liquid separator 15 via refrigerant pipe 30,throttling valve 31, evaporator 32 and refrigerant pipe 33. In this design, more heat can be removed at high pressure side of the refrigerant cycle, thus leading to a higher cooling effect. However, additional condenser, high-speed motors and fans for heat dissipation have to be provided which will result in higher initial cost and operating cost.
It is worthwhile to develop another method for the improvement of efficiency of heat dissipation and EER with less cost.
It is the object of present invention to provide a pressure accumulator at high pressure side and waste heat re-use device for vapor compressed air conditioning or refrigeration equipment, wherein superheated refrigerant vapor after the compression by compressor is introduced into said pressure accumulator for the maintaining of pressure of high pressure side. Furthermore, under a system pressure higher than conventional device for superheated refrigerant vapor, heat dissipation is carried out at higher air quantity and higher temperature difference. In addition, the efficiency of heat dissipation can be increased due to the higher pressure of saturated refrigerant. The sub-cool state of refrigerant can be attained after a substantial removal of heat through condenser.
The above object of present invention can be obtained by the provision of a pressure accumulator at high pressure side for vapor compressed air conditioning or refrigeration equipment, wherein one end of said pressure accumulator is connected to the discharge end of a compressor via a refrigerant pipe; the other end of said pressure accumulator being connected to a input end of a condenser via a refrigerant pipe with a smaller diameter than above-mentioned pipe. The refrigerant compressed by compressor becomes superheated vapor with high temperature and high pressure, and enters into said pressure accumulator via a refrigerant pipe connected between compressor and accumulator. In this case, the pressure loss will not be so apparent due to the few heat dissipation and temperature reduction. There is a flow-rate control device provided within the condenser tube of said condenser for the regulation of refrigerant flow such that the pressure within condenser tube, after the refrigerant entering from said pressure accumulator, will not be reduced too much in view of heat dissipation. Air is introduced at higher velocity to the condenser for the heat dissipation of refrigerant gas within condenser tubes, by the rotation of a high-speed fan fixed on a frame. As the refrigerant is influenced by the accumulated pressure within the pressure accumulator, the pressure drop within condenser tubes will not be so significant. The heat dissipation of refrigerant can be conducted at higher temperature and higher pressure. Under the same outside air temperature condition, a substantial amount of heat of refrigerant can be removed due to the temperature difference between air temperature and refrigerant temperature being larger than that of conventional, and due to the larger quantity and of air faster velocity being provide by a fan than that of a conventional propeller fan.
Furthermore, the refrigerant before entering the condenser, and after leaving evaporator can be conducted an exchange within liquid dipping type heat exchanger. Thereby, waste heat can be re-used for the later, and further heat can be dissipated for the former such that the refrigerant can be vaporized almost (or completely) before entering (return to) the inlet of compressor.
Therefore, this invention can assure the improvement of efficiency of heat dissipation and the increasing of cooling capacity as well as EER value.